Whenever an athlete is playing on the last year of his or her contract, it is crucial to have a good season in order to parlay that success into a long-term deal.

No matter a player's age, if he shows he can perform at a substantial level, he will greatly enhance his chances of a lucrative extension.

Every free-agent class has its top-tier players, but for every good player that maintains their previous levels of excellence, such as Cole Hamels and Zack Greinke, there are guys who do not perform as well when the money is on the line.

There are a variety of reasons why these players fail. Whether it is age, luck or simply an inability to handle the big moments, their stats do not live up to their expectations heading into the season.

Here are five guys who are having disastrous seasons in their contract year.

Boston Red Sox 1B/3B Kevin Youkilis

After two injury-plagued, subpar seasons during which he missed a combined 102 games, 2012 was going to be a huge season in determining his immediate future.

Thus far, things could not have gone any worse.

Not only does Youkilis have career lows in batting average, on-base and slugging percentage at .212/.295/.391 respectively, but he has already missed around 45 percent of Boston's games this season.

Making matters worse is that his replacement Will Middlebrooks has virtually Wally Pipp'd Youkilis, hitting .292 with a .492 slugging percentage in his place.

With all the trade rumors surrounding Youkilis, it is clear his future is not in Boston. Considering how poorly his season has gone so far, it is hard to imagine a 33-year-old Youkilis landing a long-term deal as he heads toward free agency.

St. Louis Cardinals 1B/OF Lance Berkman

2 of 5

Before the 2011 season, many so-called "experts" thought Lance Berkman was finished, with ESPN calling his signing that offseason a "gamble."

After two consecutive seasons marred by injury, it was hard to blame them, but 2011 turned out to be one of the best seasons in Berkman's career. He hit 31 home runs, drove in 94, and signed a one-year extension with St. Louis to prove that it was no fluke.

However, only signing a one-year deal has not worked out for Berkman, as it appears his 2011 was more of an aberration than a revelation. Berkman injured his knee stretching for a routine ground ball at first and is projected to miss six to eight weeks.

Just one year after Berkman finished seventh in the MVP voting, his agent will have a tough time getting a big-time contract for his client.

Detroit Tigers OF Delmon Young

3 of 5

After finishing in the top three of Baseball America's top 100 prospects an incredible four times, Delmon Young was headed for stardom.

He had everything you could want in a player. Speed, power, the ability to hit for average. When he was a mere 20 years old, he hit .316 with eight homers and 22 steals in half a season at Triple-A.

Twenty years old!

However, outside of his 2010 season, when he hit .298 with 112 RBI and his incredible showing in Detroit's playoff run last season, he has been a shadow of that player the rest of his career.

This year was supposed to be the year he would finally break out and build off the 2011 postseason to become a consistent, All-Star-caliber player.

Unfortunately for the Tigers, there is no fairy-tale ending in this story.

Young got off to a slow start with the bat, and to make matters worse, he got arrested in New York City and was suspended for seven games.

It should be easy for a player that oozes talent like Young to secure a long-term deal but instead, he has the look of a player who will never be able to live up to his vast potential.

Seattle Mariners OF Ichiro Suzuki

Despite coming over from Japan at the age of 27, he has had himself a Hall of Fame career with 10 straight 200-hit seasons and will soon have himself 2,500 hits in just 12 years in MLB action.

Having said that, he is in a precipitous decline, and after starting the year with nine hits in his first 22 at-bats, he has slumped to a .259 average.

Before 2011, Ichiro had never hit below .303, but last season he saw his average, on-base percentage and slugging percentage drop to career lows. Suzuki needed a bounce-back 2012 in order to get the multi-year deal or even a big one-year deal this offseason.

Because he is still such a big name and huge fan favorite, it would not surprise me if he sticks in Seattle. However, if he turned in one of his classic seasons, he would have been able to land a much bigger deal in spite of his age (38).

Detroit Tigers RP Jose Valverde

5 of 5

Heading into 2012, Jose Valverde was not only coming off the greatest season of his career, but one of the best seasons a closer has had in MLB history and had himself lined up for a nice payday.

Not only did Valverde lead the league in saves, but he did not blow a single opportunity, going 52-for-52 in save chances including the postseason.

However, unfortunately for both Valverde and the Tigers, this year he has been awful. As ESPN points out, Valverde has never posted a worse K-BB ratio, his velocity is down from where it was in 2009 and 2010, and he is allowed a tremendous amount of hard-hit balls with a .229 well-hit average this season as compared to .149, .143, and .145 in the last three seasons respectively.

For a reliever who will be 35 at the start of next season, Valverde already would have had a tough time getting a multi-year deal. However, after his pronounced struggles this season, he may not even be able to land a closer's job; just ask fellow closer turned set-up man Francisco Rodriguez.